Good luck! It's pretty funny having the two cars - we got a lot of stares from the neighbors, especially when we were leaving them out to soak in some sun and help the new tint set in.
I never tinted my P5. I wish that I did now though - it's amazing how much better it makes the car look. Though my main reasoning for tint is to protect the black leather interior. Don't want it drying up and cracking or fading!
that's what we had in IL and that was the biggest reason I didn't tint the P5. I figured it'd look terrible. Luckily, there's a new IL law so I can do 35% all around.